U.S. patent application number 15/471575 was filed with the patent office on 2017-10-05 for flanged heart tissue blocker.
The applicant listed for this patent is HeartWare, Inc.. Invention is credited to Lance Lynn ANDRUS, Jeffrey A. LAROSE.
Application Number | 20170281840 15/471575 |
Document ID | / |
Family ID | 58503737 |
Filed Date | 2017-10-05 |
United States Patent
Application |
20170281840 |
Kind Code |
A1 |
LAROSE; Jeffrey A. ; et
al. |
October 5, 2017 |
FLANGED HEART TISSUE BLOCKER
Abstract
An apparatus for protecting heart tissue from an implanted inlet
element of a blood pump. The apparatus includes a flange member
having a first radially constricted configuration and a second
radially expanded configuration, the flange member being biased in
its second radially expanded configuration. The flange member
defines an opening there through sized to receiving the inlet
element of the blood pump. A retaining element extending from the
flange member is included, the retaining element being flexible and
sized to be disposed about at least a portion of the inlet
element.
Inventors: |
LAROSE; Jeffrey A.;
(Sunrise, FL) ; ANDRUS; Lance Lynn; (Southborough,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HeartWare, Inc. |
Miami Lakes |
FL |
US |
|
|
Family ID: |
58503737 |
Appl. No.: |
15/471575 |
Filed: |
March 28, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62315260 |
Mar 30, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/0243 20130101;
A61B 17/02 20130101; A61M 1/1008 20140204 |
International
Class: |
A61M 1/10 20060101
A61M001/10; A61B 17/02 20060101 A61B017/02 |
Claims
1. An apparatus for protecting the heart from an implanted inlet
element of a blood pump comprising: a flange member having a first
radially constricted configuration and a second radially expanded
configuration, the flange member being biased in its second
radially expanded configuration, the flange member defining an
opening there through sized to receiving the inlet element of the
blood pump; and a retaining element extending from the flange
member, the retaining element being flexible and sized to be
disposed about at least a portion of the inlet element.
2. The apparatus of claim 1, further comprising a mounting element
configured for fastening to an exterior surface of the wall of the
heart independently of the flange member and the retaining element,
the mounting element being configured to retain the implanted inlet
element in position relative to the heart, the retaining element
being configured to engage the mounting element.
3. The apparatus of claim 2, wherein the mounting element defines a
bore and is sized to receive the implanted inlet element and the
retaining element within the bore.
4. The apparatus of claim 3, wherein the mounting element includes
a clamp configured to constrict the bore and engage the retaining
element between the implanted inlet element and the mounting
element.
5. The apparatus of claim 1, wherein the retaining element defines
a tubular body having a proximal end and a distal end, and wherein
the tubular body defines an annular pocket distal to the distal end
of the tubular body, and wherein the flange member includes a
flexible washer disposed within the annular pocket.
6. The apparatus of claim 5, wherein the tubular body includes a
plurality of perforation lines extending distally from the proximal
end of the tubular body.
7. The apparatus of claim 1, wherein the retaining element includes
at least one from group consisting of a knitted material and
polyester.
8. The apparatus of claim 1, wherein the flange member includes a
plurality of radially disposed ribs, wherein the ribs are
configured to bias the flange member in its radially expanded
configuration.
9. The apparatus of claim 1, wherein the flange member includes a
plurality of radially disposed apertures, the radially disposed
apertures being sized to promote cardiac tissue ingrowth.
10. The apparatus of claim 1, further including a flexible layer of
material circumferentially disposed around a portion of the
retaining element, the flexible layer of material configured to
prevent seepage of blood from the heart into an interior of the
retaining element.
11. A method implanting an apparatus for protecting the heart from
an implanted inlet element of a blood pump comprising: advancing a
flange member in a radially constricted configuration through an
opening of a heart wall, the flange member including a retaining
element defining a tubular body extending proximally out of the
heart through the opening, the flange member being configured to
transition to a radially expanded configuration after passage
through the opening of the heart wall; and positioning the flange
member and the retaining element to overlie an interior surface of
the heart wall surrounding the opening.
12. The method of claim 11, further comprising mounting the inlet
element of the blood pump to the heart, and wherein mounting of the
inlet element of the blood pump further includes advancing the
inlet element through the opening of the heart wall beyond the
flange member.
13. The method of claim 12, wherein mounting the inlet element
includes fastening a mounting element on the exterior of the heart
wall independently of the flange member.
14. The method of claim 13, wherein mounting the inlet element
further includes engaging the mounting element to retain the inlet
element in position relative to the mounting element and to retain
the retaining element in position relative to the mounting
element.
15. The method of claim 14, wherein fastening the mounting element
to the heart is performed before advancing the flange member
through the opening in the heart wall, and wherein the mounting
element defines a bore, and wherein the flange member is advanced
through the bore into the opening and the retaining element extends
through the bore after advancement of the flange member through the
opening.
16. The method of claim 15, wherein engaging the mounting element
includes constricting the bore of the mounting element to retain
the retaining element between the inlet element and the bore of the
mounting element.
17. The method of claim 16, further comprising separating a portion
of the tubular body adjacent a proximal end of the tubular body
remote from the flange member into strips and folding the strips
outwardly from the tubular body.
18. The method of claim 17, wherein advancing the flange member
through the opening of the heart wall further includes: placing the
flange member within a guiding tube having an open distal end;
advancing the open end of the guiding tube through the opening of
the heart wall; and advancing the flange member through the open
distal end of the guiding tube.
19. The method of claim 11, wherein the flange member is resilient
and biased in the radially expanded configuration.
20. An apparatus for protecting the heart from an implanted inlet
element of a blood pump comprising: a flange member having a first
radially constricted configuration and a second radially expanded
configuration, the flange member being biased in its second
radially expanded configuration, the flange member defining an
opening there through sized to receiving the inlet element of the
blood pump, the flange member defining an annular pocket and
including a flexible washer disposed within the annular pocket, the
flexible washer including a plurality of radially disposed ribs and
apertures; and a retaining element extending proximally from the
flange member, the retaining element being flexible and radially
disposed about the opening, the retaining element defining a
tubular body defining a plurality of tearable strips, the tubular
body defining a lumen coaxial with the opening of the flange
member.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is related to and claims priority to U.S.
Provisional Patent Application Ser. No. 62/315260, filed Mar. 30,
2016, entitled FLANGED HEART TISSUE BLOCKER, the entirety of which
is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] n/a
TECHNICAL FIELD
[0003] The present invention relates to components and methods used
in connection with implanted heart devices, such as ventricular
assist devices and other associated elements.
BACKGROUND
[0004] The heart is sometimes incapable of providing sufficient
pumping capacity to meet the needs of the body. The effects of this
inadequacy can be alleviated by providing a mechanical pump
referred to as a mechanical circulatory support device ("MCSD"). An
MCSD can be implanted to supplement the pumping action of the
heart, most commonly for an extended period of time such as several
years.
[0005] An MCSD is most commonly connected to the left ventricle. In
this arrangement, an inlet end of the pump, or an inlet cannula
connected to the inlet end of the pump, is implanted in the wall of
the ventricle, such as at the apex of the ventricle. An outlet
cannula is connected between the outlet end of the pump and an
artery such as the aorta. MCSDs which are connected to a ventricle
commonly are referred to as ventricular assist devices or "VADs."
During operation, the MCSD assists the heart to pump blood from the
left ventricle to the aorta.
[0006] MCSDs are typically connected to the heart through the use
of a mounting element such as a mounting ring. In use of such a
mounting ring, the mounting ring is secured to the outside of the
heart by suturing or other fastening techniques. A separate
surgical tool is used to core a hole in the heart within the ring.
An inlet cannula or other inlet element of the MCSD may then be
inserted through the hole into the heart. The mounting ring may
then be tightened to secure the MCSD to the ring and thus secure
the MCSD to the heart.
[0007] In some instances, the heart wall, thrombus disposed on the
heart wall, or other tissues or deposits may be drawn into the
inlet element. Tissues or deposits drawn into the inlet element may
block the flow of blood into the inlet element and may cause other
complications.
SUMMARY
[0008] The present invention advantageously provides an apparatus
for protecting heart tissue from an implanted inlet element of a
blood pump. The apparatus includes a flange member having a first
radially constricted configuration and a second radially expanded
configuration, the flange member being biased in its second
radially expanded configuration. The flange member defines an
opening there through sized to receiving the inlet element of the
blood pump. A retaining element extending from the flange member is
included, the retaining element being flexible and sized to be
disposed about at least a portion of the inlet element.
[0009] In another aspect on this embodiment, a mounting element is
included configured for fastening to an exterior surface of the
wall of the heart independently of the flange member and the
retaining element, the mounting element being configured to retain
the implanted inlet element in position relative to the heart, the
retaining element being configured to engage the mounting
element.
[0010] In another aspect on this embodiment, the mounting element
defines a bore and is sized to receive the implanted inlet element
and the retaining element within the bore.
[0011] In another aspect on this embodiment, the mounting element
includes a clamp configured to constrict the bore and engage the
retaining element between the implanted inlet element and the
mounting element.
[0012] In another aspect on this embodiment, the retaining element
defines a tubular body having a proximal end and a distal end, and
wherein the tubular body defines an annular pocket distal to the
distal end of the tubular body, and wherein the flange member
includes a flexible washer disposed within the annular pocket.
[0013] In another aspect on this embodiment, the tubular body
includes a plurality of perforation lines extending distally from
the proximal end of the tubular body.
[0014] In another aspect on this embodiment, the retaining elements
includes at least one from group consisting of a knitted material
and polyester.
[0015] In another aspect on this embodiment, the flange member
includes a plurality of radially disposed ribs, wherein the ribs
are configured to bias the flange member in its radially expanded
configuration.
[0016] In another aspect on this embodiment, the flange member
includes a plurality of radially disposed apertures, the radially
disposed apertures being sized to promote cardiac tissue
ingrowth.
[0017] In another aspect on this embodiment, a flexible layer of
material circumferentially disposed around a portion of the
retaining element is included, the flexible layer of material
configured to prevent seepage of blood from the heart into an
interior of the retaining element.
[0018] In another embodiment, a method implanting an apparatus for
protecting heart tissue from an implanted inlet element of a blood
pump includes advancing a flange member in a radially constricted
configuration through an opening of a heart wall, the flange member
including a retaining element defining a tubular body extending
proximally out of the heart through the opening, the flange member
being configured to transition to a radially expanded configuration
after passage through the opening of the heart wall. The flange
member and the retaining element are positioned to overlie an
interior surface of the heart wall surrounding the opening.
[0019] In another aspect of this embodiment, the method further
includes mounting the inlet element of the blood pump to the heart,
and wherein mounting of the inlet element of the blood pump further
includes advancing the inlet element through the opening of the
heart wall beyond the flange member.
[0020] In another aspect of this embodiment, mounting the inlet
element includes fastening a mounting element on the exterior of
the heart wall independently of the flange member.
[0021] In another aspect of this embodiment, mounting the inlet
element further includes engaging the mounting element to retain
the inlet element in position relative to the mounting member and
to retain the retaining element in position relative to the
mounting member.
[0022] In another aspect of this embodiment, fastening the mounting
element to the heart is performed before advancing the flange
member through the opening in the heart wall, and wherein the
mounting element defines a bore, and wherein the flange member is
advanced through the bore into the opening and the retaining
element extends through the bore after advancement of the flange
member through the opening.
[0023] In another aspect of this embodiment, engaging the mounting
element includes constricting the bore of the mounting element to
retain the retaining element between the inlet element and the bore
of mounting element.
[0024] In another aspect of this embodiment, the method further
includes separating a portion of the tubular body adjacent a
proximal end of the tubular body remote from the flange member into
strips and folding the strips outwardly from the tubular body.
[0025] In another aspect of this embodiment, advancing the flange
member through the opening of the heart wall further includes
placing the flange member within a guiding tube having an open
distal end; advancing the open end of the guiding tube through the
opening of the heart wall; and advancing the flange member through
the open distal end of the guiding tube.
[0026] In another aspect of this embodiment, the flange member is
resilient and biased in the radially expanded configuration.
[0027] In yet another embodiment, an apparatus for protecting heart
tissue from an implanted inlet element of a blood pump includes a
flange member having a first radially constricted configuration and
a second radially expanded configuration, the flange member being
biased in its second radially expanded configuration, the flange
member defining an opening there through sized to receiving the
inlet element of the blood pump, the flange member defining an
annular pocket and including a flexible washer disposed within the
pocket, the flexible washer including a plurality of radially
disposed ribs and apertures. A retaining element extends proximally
from the flange member, the retaining element being flexible and
radially disposed about the opening, the retaining element defining
a tubular body defining a plurality of tearable strips, the tubular
body defining a lumen coaxial with the opening of the flange
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The present application will become better understood with
regard to the following description and accompanying drawings in
which:
[0029] FIG. 1 is a perspective view of apparatus in accordance with
one embodiment of the application;
[0030] FIG. 2 is another perspective view of the apparatus of FIG.
1;
[0031] FIG. 3 is another perspective view of the apparatus of FIGS.
1 and 2 in conjunction with an MCSD;
[0032] FIGS. 4 and 5 are diagrammatic cross-sectional views
depicting portions of the apparatus of FIGS. 1 and 2;
[0033] FIG. 6 is a view similar to FIGS. 4 and 5 but depicting the
apparatus in conjunction with an MCSD;
[0034] FIG. 7 is a cross-sectional view of another apparatus
according to a further embodiment of the invention;
[0035] FIG. 8 is a flow diagram in accordance with aspects of the
application; and
[0036] FIG. 9 is a diagrammatic perspective view of a component
according to yet another embodiment of the application.
DETAILED DESCRIPTION
[0037] Referring now to the drawings in which like designators
refer to like elements, there is shown in FIG. 1 an apparatus for
protecting heart tissue from an implanted inlet element of a blood
pump constructed in accordance with the principles of the present
application and designated generally as 100. The apparatus 100 may
include a flange member 10 and a retaining element 12, which in one
embodiment, define a hollow tubular body 14. The member 10 has an
inner edge 16 that defines an opening 18 into the hollow tubular
body 14. The flange member 10 also has an outer edge 20 that
defines a radial extent of flange member 10. The tubular body 14
may be composed of a flexible material such as composed of one or
more layers of a biocompatible fabric, plastic, or metal. For
example, tubular body 14 may be composed of one or more composite
layers of knitted polymers, such as polyethylene terephthalate
("PET").
[0038] Continuing to refer to FIG. 1, tubular body 14 has a distal
end 22 and a proximal end 24. The tubular body 14 has interior
diameter large enough to pass the inlet element of an MCSD as
discussed below, typically on the order of 16-20 mm. In one
configuration, the tubular body 14 is flexible but has sufficient
stiffness to retain its shape so that it does not bend or close
under the influence of gravity. A fabric may be provided with a
medically acceptable coating such as a lacquer to increase its
stiffness. For example, the retaining element 12 may include a
flexible layer of material 26, for example, silicone, impregnated
within the fabric that defines the retaining element 12 or
otherwise is circumferentially disposed around a portion of the
retaining element 12. The flexible layer of material 26 is
configured to prevent seepage of blood from the heart into an
interior of the retaining element 12. In one configuration, the
flexible layer of material 26 defines a height greater than the
thickness of the heart well. Alternatively or additionally, the
retaining element 12 may include multiple layers of fabric. A
plurality of tear lines 28 may extend from the proximal end 24, at
least of part of the distal to the distal end 22. The material of
the tubular body 14 may be weakened along the tear lines 28, so as
to allow at least a portion of tubular body 14 adjacent the
proximal end 24 to be separated into teardown strips 30 during use,
as further discussed below. For example, the material of the
tubular body 14 may be perforated, scored or partially cut along
the tear lines 28 during manufacture.
[0039] The tubular body 14 includes an annular pocket 32 adjacent
distal end 22 and distal to the tear lines 28. Annular pocket 32
extends around the tubular body 14. For example, where the tubular
body 14 is formed from a textile, the annular pocket 32 may be
manufactured on a tubular knitting machine so that the annular
pocket 32 can be formed during manufacture, without stretching the
material of the tubular body. In one configuration, the flange
member 10 is composed of a flexible washer 34 that is disposed in
the annular pocket 32 so that the flange member 10 includes both
the flexible washer 34 and the material of the tubular body 14
forming the annular pocket 32. Flexible washer 34 may be composed
of any number of flexible materials, including rubbers, polymers
such as PET or silicone. Flexible washer 34 may have a thickness
that allows for sufficient flexibility and radial constriction as
discussed below. For example, the flexible washer 34 may have a
thickness between 2 and 3 millimeters. Washer 34 may further
include interior diameter equal to or slightly greater than the
interior diameter of tubular body 14. During manufacture, flexible
washer 34 may be positioned within annular pocket 32 while the
annular pocket 34 is open as shown in FIG. 4. Once flexible washer
34 is positioned within the annular pocket 34, it optionally may be
bonded or sewn into place. For example, where the tubular body 14
includes a portion projecting distally beyond the annular pocket
32, this portion may be folded back proximally within the tubular
body 14 so as to cover the inner edge 16 of flexible washer 34. The
folded flexible material may then be sewn or otherwise attached to
the inside portion of tubular body 14, so as to maintain flexible
washer 34 within annular pocket 32.
[0040] Continuing to refer to FIG. 1, a mounting ring 200 may be
included and configured to engage at least a portion of the
retaining element 12. The mounting ring 200 may a conventional
mounting ring as, for example, the a mounting ring as disclosed in
U.S. Published Patent Application Nos. 2004/0171905, 2007/0134993,
and 2015/0112120, the disclosures of which are hereby incorporated
by reference herein. The mounting ring has a body 202 with elements
defining a bore 204 extending through the body 202, and also has
features which can be used to attach the body 202 to the outside of
the heart wall so that the bore 204 extends towards and away from
the wall. In the example shown, the body 202 includes with a base
plate 206 on a distal side of the ring 200 which faces toward the
heart when the ring 200 is installed, and a ring of fabric
schematically indicated in broken lines at 208 attached to the base
plate 206 and encircling the body 202. A mounting ring 200 of this
type can be secured in place by suturing the fabric ring to the
exterior of the heart. Other mounting rings are equipped with barbs
or other fasteners for attaching the body of the ring to the heart
wall. The mounting ring is arranged so that a portion of the body
defining at least part of the main bore 204 is compressible to
constrict the bore 204 around an inlet element of the MCSD to hold
the element in place. As shown, for example, in U.S. Published
Patent Application No. 2007/0134993, the body 202 may include
deformable elements such as a pair of generally C-shaped arms (not
shown) on opposite sides of the bore 204, so that the bore 204 can
be constricted by forcing the arms toward one another. The body 202
may also include an element referred to as a gimbal ring (not
shown) defining all or part of bore 204, the gimbal ring be
arranged to tilt through a limited range of motion relative to the
base plate 206 to allow the inlet element of the to tilt relative
to the base plate 206 during installation. The mounting ring 200
may further includes a clamp 210 (FIG. 6) configured to deform the
body 202 so as to constrict the bore 204. A guiding tube 300 (FIG.
5) formed from a substantially rigid material such as a metal and
having an outside diameter may be included and configured to fit
within the bore 204 of the mounting ring 200 while the bore 204 is
in an unconstructed state. Guiding tube 300 may include a thin wall
and may further include a stop member 302 projecting outwardly
adjacent a proximal end of the guiding tube 300. A pusher tube 304,
also formed from a thin, rigid material, is slidably received
within guiding tube 300. The pusher tube 304 may have a stop 306
projecting outwardly at its proximal end.
[0041] In a method according to a further aspect of the disclosure,
schematically depicted in the flow chart of FIG. 8, the mounting
ring 200 may fixed to the to the outer surface 36 of heart wall 38
(FIG. 5), such as by suturing fabric ring 208 to the heart wall 38
(step 802). A coring tool (not shown) is used to form a hole in the
heart wall 38 in alignment with the bore 204 of the mounting ring
200 (step 804). The flange member 10 may be deformed from a second
radially expanded configuration in which the flange member is
biased in a radially expanded configuration or condition (depicted
in FIGS. 1-4) to a first radially constricted configuration or
condition depicted in FIG. 5 (step 806). In this radially
constricted condition, the flange member 10 has a diameter less
than the diameter of the bore 204. In this condition, the distal
end 22 of tubular body 14 may be partially or completely collapsed.
The flange member 10 and the distal end 22 of retaining element 12
are passed through the bore 204 of the mounting ring 200 and
through the hole in the heart wall 38, while leaving the proximal
end 24 of the retaining element 12 outside of the heart and
proximal to the mounting ring 200 (step 808). This may be done by
positioning the tubular body 14 inside guiding tube 300 and pusher
tube 304, with the flange member 10 disposed distal to the pusher
tube 304, and advancing the guiding tube 300 through the mounting
ring 200 until the distal end of the guiding tube 300 is just
inside the heart, i.e., just past the interior surface the heart
wall as depicted in FIG. 5. The stop member 302 of the guiding tube
300 may engage the proximal side of the mounting ring body 202 to
prevent excessive advancement of the guiding tube 300. The flange
member 10 may be brought to its radially-expanded condition and
positioned to overlie the interior surface of the heart wall 38.
This can be done by advancing pusher tube 304 within the guiding
tube 300, so as to push the flange member 10 out of the guiding
tube 300 through its distal end. The inner surface of guiding tube
300 may have a low coefficient of friction with flange member 10 so
as to allow the flange to easily slide through guiding tube
300.
[0042] When the flange member 10 is clear of the guiding tube 300,
the flange member 10 transitions back to its radially-expanded
condition. Stop member 302 on the pusher tube 304 may engage the
pusher tube 304 and arrest the distal movement of the pusher tube
304 when the distal end of the pusher tube 304 reaches the distal
end of the guiding tube 300. Once the annular washer 34 has been
ejected from the guiding tube 300, the guiding tube 300 and pusher
tube 304 may be removed by sliding them proximally relative to the
mounting ring 200 and retaining element 12. The physician may, for
example, manually grasp the retaining element 12 adjacent its
proximal end and pull it proximally to seat the annular washer 34
against the interior surface. At this stage of the process, the
apparatus 100 has the configuration shown in FIG. 1.
[0043] The proximal end 24 of the retaining element 12 may be
separated into strips 30, by tearing along tear lines 28 (FIG. 4),
and the strips 30 may be folded outwardly, away from the bore of
the mounting ring 200, to the configuration depicted in FIG. 2
(step 812). In this condition, the retaining element 12 does may
not protrude from the proximal end of the mounting ring 200. The
physician may maintain the position of the flange member 10 within
the heart by holding one or more of the strips 30. Alternatively,
the physician may suture one or more of the strips 30 to the fabric
ring 208 of the mounting ring 200, or to the exterior surface of
the heart wall 38.
[0044] An inlet element 400 (FIG. 3) of an MCSD 401, such as an
inlet element or inflow cannula 400 of MCSD 401 may then be
advanced into the opening of heart wall 38 through the bore 204 of
the mounting ring 200 and inside of tubular body 14, until a
portion of the inflow cannula 400 is disposed within the heart
chamber (Step 814). The particular MCSD 401 depicted includes a
centrifugal flow pump having a body with a rotor disposed therein
and an elongated inlet element projecting from the body and having
an inlet opening at its end remote from the body (FIG. 3). Because
the tubular body 14 does not project proximally from the mounting
ring 200, the pump may be advanced until body is proximate to or
abutting the proximal side of the mounting ring 200, so that the
assembly of the pump and mounting ring 200 forms a compact
structure on the outside of the heart. At this stage, the wall of
tubular body 14 resides between inlet member and mounting ring 200,
as best appreciated with reference to FIG. 6. Once MCSD 401 is in
place, clamp 210 is actuated to constrict the bore of mounting ring
200 so that at least a portion of mounting ring 200 is tightened
around inflow cannula 400 to securing MCSD 401 into place relative
to mounting ring 200 and relative to the heart (Step 816).
[0045] Prior to clamping mounting ring 200 onto inflow cannula 400,
the apparatus 100 may move independently of mounting ring 200.
However, when mounting ring 200 is clamped onto inflow cannula 400,
tubular body 14 is secured into a fixed position between mounting
ring 200 and inflow cannula 400. Thus, tubular body 14 may continue
to maintain the position of flange member 10 against inner surface
of heart wall 38. While flange member 10 and inflow cannula 400 are
each positioned against opposite sides of heart wall, flange member
10 is not squeezing, or is only slightly squeezing, heart wall 38
against mounting ring 200. Because the mounting ring 200 is
fastened to the heart wall 38 independently of the flange member
10, the flange member 10 need not bear forcibly on the inside of
the heart wall 38 to hold the mounting ring 200 and MCSD 401 in
place. By limiting the squeezing force that is applied to the heart
wall 38 by flange member 10 and mounting ring 200, the potential
for necrosis of heart tissue may be reduced. Once in position,
flange member 10 may block heart tissues or deposits such as
thrombus from entering the opening of the inflow cannula 400. In
particular, the portion of heart wall 38 that flange member 10
directly overlies may be prevented from being drawn into opening
402 of inflow cannula 400 during operation of MCSD 401. Flange
member 10 may also retard growth or deposition of tissue or
thrombus around inflow cannula 400.
[0046] The apparatus and methods discussed above can be varied in
numerous ways. For example, the flange member 10 can be brought to
its radially constricted condition and advanced through the
mounting ring 200 and through the opening in the heart wall 38
manually or with the use of tools other than the guiding tube 300
and pusher tube 304 discussed above. In a further variant, the
mounting ring 200, the tubular body 14 or both can be provided with
fasteners to hold the strips 30 in place temporarily from the time
the strips 30 are folded over to the time the clamp 210 is
actuated. For example, the ends of the strips 30 at the proximal
end of the tubular body 14 may be provided with hook and loop
fasteners and mating fasteners can be provided on the mounting ring
200. In another variant, the strips 30 may have sufficient
stiffness such that they will remain in place once folded over the
proximal end of the mounting ring 200, and the folded strips 30 may
maintain position of the flange member 10 without any fastening.
Conversely, the strips 30 may have sufficient length to extend
beyond the area covered by the body of the MCSD 401, so that the
physician can readily hold them while seating the MCSD 401 in the
mounting ring 200.
[0047] The cored hole within heart wall 38 may be any diameter
desired for affixing inflow cannula 402 of MCSD 401. For many MCSDs
401, the cored hole may be approximately 18 mm in diameter. As set
forth above, flange member 10 may be configured so that it may be
radially constricted to an extent that will allow flange member 10
to pass through the 18 mm diameter hole. Flange member 10 may also
be configured so that once flange member 10 is in a position
overlying inner surface of heart wall 38 that it will radially
expand to a sufficient extent so as to prevent heart wall material
from entering inlet opening 402. For example, flange member 10 may
have a diameter of 35-40 mm or more in its radially expanded
condition. The diameter of tubular body 14 may also vary depending
on the dimensions of inflow cannula 400 and cored opening in heart
wall 38. For example, if the cored opening in heart wall 38 is 18
mm the tubular body 14 may have a diameter around 18-20 mm.
[0048] While FIGS. 1-6 show flange member 10 as having a circular
shape of uniform thickness, flange member 10 may be configured to
have any number of shapes in accordance with aspects of the
disclosure. For example, FIG. 7 shows apparatus having a flange
member 10 that varies in thickness in the radial direction, so as
to decrease in thickness from inner edge 16 to outer edge 20. This
variation in thickness may be configured so that flange member 10
may be more readily constricted in the radial direction during
passage through the cored opening of heart wall 38. The flange
member 10 may be have non-circular shape. For example, the flange
member 10 in its radially-expanded condition may take the shape of
a triangle, square, or multi-pointed star. The flange member 10 may
also include a plurality of arms (not shown) that may be
constricted radially so as to allow flange member 10 to pass
through an opening of a heart wall, but which mechanically extend
out radially from the flange member 10 after passage through the
opening.
[0049] Returning to FIG. 1, tubular body 14 may be provided with
any number of tear lines 28. For example, three or four tear lines
28 may be provided so as to create three to four strips 30. In
addition, only some of the tear lines 28 may be torn during
installation, so as to create fewer teardowns but wider strips 30.
In addition, the flexible material of tubular body 14 may be
covered in a lacquer (not shown), so as to stiffen the flexible
material and allow for the tubular body 14 to maintain a given
shape after placement within the heart wall 38. It is not essential
to provide the tear lines 28 during manufacture; the physician may
simply cut the tubular body 14 during installation to form the
strips 30. In a further variant, the retaining element 12 such as
the tubular body 14 may be crumpled axially or everted during
installation so as to reduce projection of the tubular body 14 from
the proximal end of the mounting ring 200. Additionally, a
plurality of ribs 40 may be included on the flange member 10 and
radially disposed about the opening 18. For example, as shown in
FIG. 1, four ribs 40, which are composed of the same material as
the flange member 10 may lend additional stiffness to the flange
member 10 such that when the flange member 10 transition from the
first radially constricted condition to the second radially
expanded condition that the flange member 10 forms and maintain the
desired radially expanded configuration. Additionally, the flange
member 10 may define a plurality of apertures 42 extending through
the flange member 10 to facilitate tissue ingrowth into the flange
member 10. In the configuration shown in FIG. 1, the plurality of
apertures are radially disposed about the flange member 10.
[0050] Different MCSDs 401 may be mounted. For example, the MCSD
401 may include an axial-flow pump having a generally tubular
housing with an inlet end and an outlet end. The inlet end of such
a housing may serve as the inlet element of the MCSD 401 which is
inserted into the heart. Other MCSDs 401 include a pump which is
mounted remote from the heart and an elongated, typically flexible,
inlet cannula which serves as the inlet element of the MCSD 401.
Where such an MCSD 401 is used, the tubular retaining element may
continue to protrude proximally from the mounting ring. For
example, the proximal end of the tubular element need not be formed
into strips or folded over in the manner discussed above.
[0051] The retaining element 12 may be formed integrally with the
flange member 10. In one configuration, the retaining element 12
may incorporate a check valve such (not shown) as a leaflet valve
or duckbill valve to prevent loss of blood from within the heart
prior to insertion of the inlet element of the MCSD 401. Such a
check valve may be integral with the retaining element 12, and
arranged to allow insertion of the inlet element 400 through the
check valve. In yet another variant, the retaining element 12 is
not tubular. For example, as shown in FIG. 9 the flange member 10
and a retaining element 12 may be in the form of plural discrete
strips 30 extending proximally from the flange member 10.
[0052] Although the invention has been described above with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
disclosure. The following paragraphs further disclose certain
aspects of the invention.
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